LED modules including a plurality of LED chips, for example emitting red and blue/yellow or white light, may have a potting compound including scattering bodies contained therein (“scattering encapsulation”) for light mixing. It is known to apply the scattering encapsulation layerwise onto an underlying layer of clear potting compound, since, for the scattering encapsulation, with a fixed scattering concentration the following relationships apply: (a) the thicker the scattering encapsulation is, the better the light mixing is and (b) the closer the scattering encapsulation is applied to the LED chips, the worse the light mixing is (since the light then propagates less to the side). Typically, the layering is carried out in such a way that the LED chips are first embedded in the clear potting compound (for example silicone) and the scattering encapsulation (for example aluminum oxide in silicone) is applied on top. This is carried out in two process steps.
The specific configuration of clear potting compound and scattering encapsulation influences in particular the efficiency and the light mixing of the LED module. For good reproducibility, to this end particular measures are necessary, such as staggering of a lateral enclosure used as a potting mold, since otherwise a homogeneous layer thickness of the scattering encapsulation cannot be achieved.